The present invention relates to a mechanically scanned parabolic reflector antenna, and more particularly, the present invention relates to a mechanically scanned parabolic reflector antenna for a vehicular collision warning system.
The present construction is directed towards a motor vehicular collision warning system, which includes a scanned beam sensor, a signal processor, and a vehicle interface system that initiates warnings to the driver or adaptively controls the vehicle. In this forward looking collision warning system, the sensor is designed to project a narrow beam of energy toward objects in the forward field of view. Energy reflected from an object in the vehicle path is received by the vehicular collision warning system and processed to determine whether a collision condition exists. If a collision condition exists, the system initiates a response to the condition.
While this system acts to sense collision conditions and respond thereto, some drawbacks exist. Specifically, targets that create potential obstacles for the vehicle must be identified long before they become close to the vehicle. This is to allow the system or driver proper time to react. Specifically, the target must be sensed and responsive action must be taken far before the target becomes close to the vehicle. To meet this need, the system must be able to efficiently transmit and receive radar signals over large distances. This may require complicated and large components, thereby requiring a large amount of space on the vehicle to mount the sensing system. As conventional vehicles are limited in allowable space for such a system, this presents obvious difficulties when applying the system to a vehicle.
Therefore, it is an object of the present invention to avoid the aforementioned disadvantages and problems associated with existing wave antenna scanners.
In accordance with this invention, a radar apparatus is provided with a rotatable reflective antenna structure driven to oscillate back and forth. The antenna structure is parabolic and reflective, thereby focusing a beam of radar signals having a narrow azimuth toward a target. The radar signals are provided to the antenna structure from a transceiver coupled to the antenna structure. The antenna structure directs radar signals, reflected by the target, back to the transceiver. The scanned signals are directed to a processor and then to a vehicle interface system for initiating warnings to the driver or adaptively controlling the vehicle. The use of the reflective antenna allows the present invention to focus or direct radar signals provided from the transceiver.
In one aspect of the invention, the transceiver transmits the radar signals against a reflective plate, which in turn, directs the radar signals at the antenna structure. Radar signals reflected from the target are then directed from the antenna to the reflective plate. The reflective plate then directs the radar signals to the transceiver. Accordingly, the limited vehicle space is accommodated by advantageously positioning the system components while the parabolic antenna structure focuses the beam and minimizes energy loss.
In another aspect of the present invention, the transceiver is positioned at the focal point of the parabolic antenna, thereby omitting the reflector dish. The radar signals are transmitted directly to the antenna from the transceiver, and sent to the target by the antenna. Reflected radar signals are then reflected directly back to the transceiver from the antenna.
The foregoing and other advantages and features of the invention will be more apparent from the following description when taken in connection with the accompanying drawings.